Ruins of the Barrier
by Derpford
Summary: Twilight Sparkle perfects a spell which allows cross-universe travel. But the wacky hijinks don't just make the reader laugh-they also attract the attention of the Combine Army, the mighty military arm of an alien empire! How will the Mane Six deal with these new enemies? And who else will cross the barrier between the worlds?
1. Chapter 1

Twilight Sparkle paced throughout her library, muttering about quantum waveforms and other such buzzwords, and calling out to Spike occasionally.

"Where's that spellbook? I need to find that copy of 'Universal Universes'..."

Spike quickly pulled the book out of its hiding place-he often wondered how Twilight forgot where she threw these books, a detail which he could recall immediately. A purple glow surrounded the book, and Twi quickly yanked it out of his hand, flipping the pages until she reached a dog-eared chapter labeled "Travelling in Five Dimensions".

"Found it! Spike, get the girls in here. We're going on a trip!"

* * *

"Ah don't get it. Wha's all this got ta do with travellin' again?"

"We're going to travel to other universes!"

"Don't you mean 'dimensions'?"

"No, Rainbow Dash. Dimensions are just directions that are perpendicular to other dimensions. Universes are entire other worlds."

Twilight ushered her friends into the magic-channeling circle she had drawn on the floor. "I'm gonna teleport us all into some alternate universes, and maybe we'll find something interesting."

"Why would we find anything interesting in another universe?" Applejack asked, eyebrow raised. "Ah don't think there's much that could be different from the stuff in ours."

"Well, according to my calculations, there's an infinite number of these universes-and each one is different! We're bound to find something that's useful at some point."

"Ooh! OOH! I bet we could throw a welcome party for OURSELVES. Wouldn't that be CRAZY AMAZING SPECTACULAR-"

"I don't think there's any other universes where we exist, Pinkie," Twilight explained, "And even if there was, meeting ourselves would be bad. Probably."

"On the other hand, perhaps there are some incredibly fashionable aliens who will give me the inspiration I need."

"uh, are you sure it isn't dangerous?"

Twi nodded, trying to reassure Fluttershy. "We'll be fine. Between my magic, Rainbow Dash's speed, and AJ's strength, we can handle just about anything that could be on the other side of this portal."

Rainbow Dash nodded proudly, smiling confidently. Applejack simply adjusted her hat and said "Let's get this hoedown over with."

Fluttershy nodded back to Twilight, still a little scared. Of course, any pony would be afraid of something completely unknown.

Twilight charged the circle with magical energies. Lightning arced and crackled across the points of the hexagonal symbol within the circle, dancing along the letters etched into its surface. Fluttershy backed toward the center, as did the other ponies. The circle began glowing gently, and that glow became a bright, pulsing light. Soon the world around them blurred...and changed...and became Twilight Sparkle's library.

"um...i don't think it worked."

Twilight blinked. "I cast the spell exactly right, didn't I? We should be in some fantastic realm-"

A sound came from the bedroom, a haunting, disturbing moan.

"Maybe this wasn't tha best idea, Twi," Applejack said as she began shaking.

Fluttershy was already hiding behind Rainbow Dash, and Pinkie...where was Pinkie?

The bedroom door creaked open, as Pinkie peeked inside-and was nearly thrown against the wall by Trixie!

"What are you doing in the Great and Powerful Trixie's house?! You interrupted my beauty sleep-What in Luna's name?"

The Great and Boastful Trixie stared at the six ponies now standing in her living room, her jaw agape. "Twilight Sparkle, and Pinkie Pie, and Rarity, and-Rainbow Dash? Fluttershy? I thought you two were on your anniversary dinner date!"

There was an awkward pause. Then there were two soft "pomf"s and a "oh my".

Then there was another pause-and then Twilight finally spoke. "We're actually...how do I put this...from another version of Equestria. One where this is my house."

"Although I must say," Rarity mentioned, "Your version of this place is much better. I like what you did with those curtains!"

Everypony stared at her.

"Did you really just say that?" Rainbow Dash glared at Rarity, her embarrassment replaced with indignity.

"It seems kinda insensitive," Applejack commented.

The Great and Sensitive Trixie simply smiled. "I think it was just a well-meant compliment, really. By the way, Twilight-you should stick around until this universe's Twilight gets here. It'll be interesting, finding out what two of you can do-"

"NOTHING TO SEE HERE BYE!" And they were gone in a flash of purple.

* * *

They found themselves in the library-again-but this time, the shelves were different, and the table was higher, and the door was twice as tall.

"Did y'all just accidentally shrink us?"

"No, there wasn't any shrinking elements to the spell."

"Perhaps the room simply is bigger than we remember?"

"i have to fly to reach the door handle now..."

As Fluttershy reached pitifully for the door, it opened-and a strange creature walked out. It stood on two legs, and was twice as tall as the ponies. It wore a flowing robe, emblazoned with stars and constellations-all in the right places, Twilight noted-and a familiar symbol on one shoulder.

"What in Equestria?!" shouted Twilight-or should I say, both Twilights.

Twilight (the pony) immediately began charging the spell again-this monster thing scared her, she didn't know why, but it incited fear in the very depths of her soul. Something about meeting yourself-but-not-yourself just...unnerved her.

Another flash of violet light, and they were home. They were in their real home this time, Twilight was sure of it.

* * *

The next morning, Pinkie had organized a party to celebrate their first cross-universe travel, filled with oddly-shaped balloons, crazy music, and candy shaped like other foods (Pinkie figured that there simply must be a universe where broccoli tastes like gummi bears) along with DJ PON-3's trademark "hoofstep" music. As Rarity made small talk with some of the party guests, and Rainbow Dash chatted with Fluttershy, Twilight walked toward the edge of the partygrounds to get some fresh air.

She was the first to notice the strange guests.

They were bipedal, and wore strange metal armour, which covered their entire bodies. When one spoke, it was with a distant quality, like some of PON-3's favorite special effects, and they all carried oddly-shaped bits of metal in their hooves.

What could they possibly want? Why were there more of these things?

Out of the corner of her eye, Twi saw a pink blur. Oh, horse apples-

"Hi! What's your name? I'm Pinkamena Diane Pie, but you can call me Pinkie, which is what my friends call me, but you should call me that too because YOU'RE MY FRIEND NOW! WHEE! I should go get started on your 'Welcome to Ponyville' party. Ooh, I almost forgot the song! My name is Pinkie Pie,/ and I am here to say..."

The world moved in slow motion as the creature held the weird metal bit up, pointed it at Pinkie, and pressed a lever set into the handle.

Pinkie fell with a blood-curdling scream, and the world around Twilight erupted with panic.


	2. Chapter 2

"Is everypony okay?"

The Everfree Forest-once, Twilight would've never entered this place at night; the one time she did, she was promptly attacked by a cockatrice, and only Fluttershy's skill at handling animals prevented her from staying that way. But, in a twist of fate and accident, it was the safest place this side of Canterlot.

Soon after Pinkie hit the ground, Twilight Sparkle had called upon the skills and information she learned during the Great Changeling Invasion, casting a shield around Pinkie while throwing a few bolts of magic at the invaders.

Invaders! She hadn't thought about it at the time, but that's almost certainly what these new creatures were.

The invaders reacted to Twilight's blind shots fairly badly; it was clear that they weren't used to magic. Soon after she got to Pinkie Pie, however, the shock wore off, and they opened fire. Bits of metal slammed into Twilight's shield, almost throwing her off-balance-Holy Nightmare Moon, those things hurt-as she picked the party pony up.

"What happened...? I'm, am I bleeding?"

She's going into shock, Twilight thought. I need to find a doctor.

A few more hours of rushing around, and Twilight had learned much more about the mysterious invaders. She had also saved a few of Ponyville's citizens, including-thank Celestia-all of her friends.

She had also saved any others she could get to in time-a unicorn named Diamond Mint, Doctor Stable from the local hospital, a fencing expert named Lance, a visitor from Canterlot by the name of Neon Lights, a pegasus named Blue October...the list went on (she had Spike make a list). After everypony had checked in, she trotted toward the clearing where Fluttershy was assisting Dr. Stable in treating the wounded.

"I have never seen anything like this," he said worriedly, as Twilight approached. "How ironic! This time it's Dr. Horse on the operating table, and I'm the one who has no idea what I'm doing!" He laughed, but did not smile.

The earth pony lying in front of Stable coughed, a line of red liquid running down his cheek. "I...I do know what I was doing, Stable, you old fool...I was protecting the fillies." He coughed several more times, tears mingling with the blood. "It's a shame, really. I couldn't do anything but waste a few seconds of their time."

Off in the distance, voices could be heard-

"Where's Dinky? Where's my little muffin?"

"Pipsqueak? Where's Pipsqueak?!"

"I can't find High Score! Somepony help me find him, please!"

Meanwhile, Fluttershy rushed around the clearing, checking bandages and asking meekly if anypony needed anything.

Twilight walked to the damp, stained grass where Pinkie was lying.

"Twi?" she asked, barely aware of what was happening. "It hurts, Twi. Why does it hurt...? I just wanted to be friends-it didn't even let me finish the song."

Twilight Sparkle sighed, her own eyes wet with tears. "I don't know, Pinkie. I just don't know anything right now."

"Good thing I'm here, then."

Another of the strange bipedal creatures walked out of the bushes-but this one wore different armor, and his head was uncovered. He held one of the oddly-shaped metal things in his hand, but his finger was away from the lever, and he was pointing it deliberately at the ground, away from everypony. "My name's Gordon Freeman."

"Freeman?" Pinkie asked, weakly. "Sounds like your special talent is helping others."

Freeman chuckled. "I guess you could say that, if you really think about it."

Some of the other ponies reared away from Gordon, panicked. The ones who weren't injured were facing him, wings ready for flight and horns charged with magical energy.

He dropped the metal thing, and raised his hands over his head.

"Do with me what you will."


	3. Chapter 3

In another world, a pair of young men sit in the office of their commanding officer-no, the commanding officer.

One of the men wears a long red trenchcoat, emblazoned with the symbol of Flamel on the back, and wears his blonde hair in a long ponytail. The other wears a full set of heavy armor, and is noticeably taller.

The officer they are reporting to wears the blue greatcoat of a military officer, which has the insignia of the highest authority in the country of Amestris: the Führer, ruler of the land and commander-in-chief of Amestris's military. In particular, he commands the State Alchemists.

The nameplate on his desk reads "Roy Mustang".

"So this one researcher discovered another world?" said the short blonde one.

"Not a world, Fullmetal-a universe. It's completely separate from ours, which means that we, the country of Amestris, and our entire planet, simply never existed in this alternate universe."

"Like the world beyond the Gate, but without any connection to ours?" said the one in the armor. His voice was noticeably younger.

"That's what I got from it," said Mustang. "Our researchers in lab 5-"

The short one-Fullmetal-cringed.

"-have figured out how to send you there."

Both the tiny one and the armored one sit straight up.

"Not only that, but your alchemy will definitely work there, and you'll have an easy way back. So I'm sending you into this new world..."

Mustang struck a dramatic pose, standing on his desk and pointing towards a new frontier...

"...to find out what lies beyond!"

"You could cut down on the dramatics," Fullmetal commented.

* * *

After Freeman had been suitably restrained-Twilight was, for once, thankful for Rarity's insistence on bringing a sewing kit and plenty of cloth everywhere-they had questioned him.

These strange two-legged things were called humans-or, at least, Gordon was a human. The soldiers who had attacked them at the party were a combination of humans and another kind of creature-Gordon referred to these soldiers as the Combine.

Apparently, the Combine had already taken over Gordon's world, and he was on his way to fight their leader on his world, a human known as Dr. Breen. As Gordon was sneaking into the Combine's main fortress on his world-he called it "Earth"-he was forced to hide inside of a troop transport, pinned in his hiding place by the soldiers preparing to leave.

As luck would have it, Gordon was on one of the transports bound for Equestria, which was carrying the very platoon which had attacked Pinkie's party! He managed to escape into the woods, and found the pony encampment by sheer luck.

After this was explained, one of the other ponies-was that the owner of the quills and sofas store?-asked how the strange metal thing worked.

"This is called a gun," Gordon explained, gesturing to the small metal thing. "They come in a variety of shapes and sizes, but their main function is the same: throwing a small chunk of metal called a bullet at high speed. Some guns fire more bullets, some fire larger bullets, but they are all highly dangerous weapons."

The quill-and-sofa store owner-Davenport, that was his name-smiled. "I bet if we learned how to use those things, we'd have a better chance of stopping this Combine you've been talking about."

"How in the hay do you treat the wound, though?" Dr. Stable had joined the small herd surrounding Mr. Freeman, shoving his way to the front. "There's at least two dozen ponies who're badly hurt, and-Celestia help me-I just don't know how to treat them!"

Rarity released the human, and he walked away, earnestly explaining the intricacies of internal bleeding and organ damage to Dr. Stable.

While Gordon busied himself assisting Stable and Fluttershy, Twilight began whispering in Applejack's ear:

"Do you think we can trust him?"

"Well, he's one of them hoomans, but..." Applejack sighed. "Ah think we should let him help. I figger he's not trying to hurt us, and he already has a bone to pick with them Combine fellas. 'Sides, I could probably take 'im out with one kick, if worse gets ta worst."

"I hope you're right, Applejack." Twilight shook her head, as if to shake off a doubt. "I know you're right! You're the Element of Honesty, for Luna's sake, why would you be wrong?"


End file.
